/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 *
 * Copyright (C) 2006 by Rani Hod
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define ROCKBOX_BOOTLOADER 0x00150000
#define BOOTLOADER_LIMIT   0x00170000 

void usage()
{
  printf("Usage: x5-patch <inputfile> <outputfile>\n");
}

void do_patch(char *fbuf, const char *ibuf, size_t ilength)
{
  unsigned char *p;
  /* change jsr 0x10010 to jsr DUAL_BOOTLOADER */
  p = fbuf + 0x1030 + 2;
  *p++ = (ROCKBOX_BOOTLOADER >> 24) & 0xff;
  *p++ = (ROCKBOX_BOOTLOADER >> 16) & 0xff;
  *p++ = (ROCKBOX_BOOTLOADER >>  8) & 0xff;
  *p++ = (ROCKBOX_BOOTLOADER      ) & 0xff;

  p = fbuf + 0x1030 + ROCKBOX_BOOTLOADER - 0x10000;
  memcpy(p, ibuf, ilength);
}

int main(int argc, char **argv)
{
  size_t flength, ilength;
  unsigned char *ibuf, *fbuf;
  const unsigned char fsig[] = { /* jsr 10010 */
    0x4e, 0xb9, 0x00, 0x01, 0x00, 0x10 };
  //const unsigned char isig[] = { /* move.w #$2700, sr */
  //  0x46, 0xfc, 0x27, 0x00 };
  FILE *ifile, *ofile, *ffile;
  unsigned char sum = 0;
  int i;

  if (argc != 3)
  {
    usage();
    return 1;
  }

  if ((ifile = fopen(argv[1], "rb")) == NULL)
  {
    perror("Cannot open input file.\n");
    return -1;
  }

  fseek(ifile, 0, SEEK_END);
  ilength = ftell(ifile);
  fseek(ifile, 0, SEEK_SET);

  if (ilength + ROCKBOX_BOOTLOADER >= BOOTLOADER_LIMIT)
  {
    perror("Rockbox bootloader is too big.\n");
    return -1;
  }
 
  if ((ffile = fopen("x5_fw.bin", "rb")) == NULL)
  {
    perror("Cannot open original firmware file.\n");
    return -1;
  }
  
  fseek(ffile, 0, SEEK_END);
  flength = ftell(ffile);
  fseek(ffile, 0, SEEK_SET);

  ibuf = malloc(ilength);
  fbuf = malloc(flength);

  if (!ibuf || !fbuf)
  {
    perror("Out of memory.\n");
    return -1;
  }

  if (fread(ibuf, 1, ilength, ifile) < ilength 
    || fread(fbuf, 1, flength, ffile) < flength)
  {
    perror("Read error.\n");
    return -1;
  }
  fclose(ffile);
  fclose(ifile);

  /* verify format of input files */
  //if (ilength < 0x10 || memcmp(ibuf, isig, sizeof(isig)))
  //{
  //  perror("Rockbox bootloader format error (is it bootloader.bin?).\n");
  //  return -1;
  //}
  if (flength < 0x1030-0x10000+BOOTLOADER_LIMIT 
    || memcmp(fbuf+0x1030, fsig, sizeof(fsig)))
  {
    perror("Firmware format error.\n");
    return -1;
  }

  /* verify firmware is not overrun */
  for (i = ROCKBOX_BOOTLOADER; i < BOOTLOADER_LIMIT; i++)
  {
    if (fbuf[0x1030-0x10000+i] != 0xff)
    {
      perror("Firmware has changed too much.\n");
      return -1;
    }
  }

  do_patch(fbuf, ibuf, ilength);

  /* recalc checksum */
  for (i = 0x1030; i < flength; i++)
    sum += fbuf[i];
  fbuf[0x102b] = sum;
  
  if ((ofile = fopen(argv[2], "wb")) == NULL)
  {
    perror("Cannot open output file.\n");
    return -1;
  }
  if (fwrite(fbuf, 1, flength, ofile) < flength)
  {
    perror("Write error.\n");
    return -1;
  }
  fclose(ofile);
}